Although the world of mobile devices has been expanding over the last few years, a pattern is taking shape. That pattern is centered around four types of devices:

Laptops of various screen sizes

Netbooks, which generally have smaller screen sizes than laptops

Tablet computers, such as iPad

Smartphones, such as iPhone

Laptops and netbooks generally have keyboards built into them; tablet computers and smartphones might have small keyboards, onscreen keyboards, or the ability to connect wireless keyboards to them. Many (including iPad and iPhone) have several of these options.

The combination of the relatively smaller screen size than a desktop-based computer and the use of a smaller keyboard for input is at the heart of what you have to think about when you are developing for a mobile device. Of course, at the same time, you have to consider that these mobile devices and their owners can go many places where traditional computers cannot go. The marketplace seems to be deciding that whatever drawbacks a smaller screen size might have (and, in the case of iPad, many people would argue that the screen is just fine as is) and that the smaller keyboard might pose, the greater mobility is far worth it.

The issues of screen size and keyboard, as well as what you have to think about when you are working in a world of touch control, recur throughout this book. Anyone who develops for mobile devices has to be aware of them because it is a new way of thinking about interfaces.

This chapter deals with issues common to most mobile devices. In the next chapter, you see some of the issues that are common to both mobile devices and the FileMaker database tools.

Working with Your Fingers

Pointing with your finger and pointing with a computer are two very different experiences; neither is intrinsically better than the other. It is your job as a designer of a database solution to handle both appropriately. There are two primary issues to consider:

A computer mouse with its pointer on the screen can point much more precisely than a fingertip can. This means that clickable items on a user interface can be much smaller than tappable items on a touch interface: Fingertips are enormous compared to the tip of a pointer on a computer screen.

For most people, a fingertip can move farther and faster than a computer mouse can. Even a wireless mouse needs to be picked up and moved away from the edge of a desk when you need to move the pointer on the screen a bit further.

There is another point to consider when comparing your fingertip to a computer mouse: Although you can watch the mouse pointer move along the screen as you drag the mouse on the desk, there is no comparable behavior with a touch interface. A computer mouse can participate in mouse-up tracking (that is, the movement of the mouse and its pointer on the screen without the button being down), but if your finger is not touching the screen, its movement cannot be tracked.

This means that every aspect of an interface that relies on mouse-up tracking just does not work on a touchscreen—there are no tooltips or help tags to guide people along. (Apple uses the latter term; the tooltip term and functionality were introduced in Microsoft Word 95.)

Touching and Tapping a Mobile Screen

Mobile devices such as iPad and iPhone use touchscreens (one word). The technology is referred to as touchscreen technology and there are many variations on that phrase (people sometimes talk about a touch environment). Touch is the basic technology.

The actions that the user performs are called gestures. The two most common gestures are taps and touches. There is a distinction (and it is a distinction that you will find in a standard dictionary, although the nuances of the distinction matter more in the world of touchscreens).

A tap is a down-and-up action. For programmers, in many cases it is the up part of the action that they care about. The touchup event is what triggers an action similar to a mouse click in many applications.

A touch is the down part of a tap. It comes into play in cases where the finger remains in contact with the touchscreen. You frequently find instructions such as, "Touch and hold the image and then drag it to your document." The hold part of that command can be a very short period of time, but the touch-and-hold action is just enough to let the device understand that something else such as the drag is going to happen.

You can see how touch-and-hold works on iPhone or iPad when you touch and hold your finger over some text, as you see in Figure 4.1.

Figure 4.1 Touch and hold over some text to bring up the magnifying glass.

The text is enlarged so that you can see where the insertion point is. As you drag your finger along the screen, the magnifying glass moves so that you can see exactly where the insertion point is.

When you lift your finger up, the dragging of the magnifying glass ends, and the selection buttons appear, as shown in Figure 4.2.